|
Fetron
The Fetron was a range of solid-state, plug-compatible replacements for vacuum tubes (valves). Fetrons were manufactured by Teledyne Semiconductor from 1967; primarily as a low-maintenance and low-power swap-in to replace vacuum tubes, which were becoming increasingly obsolete and difficult to source with the widespread use of solid-state electronics. They were used in large numbers in telephone exchanges. Vacuum tubes use significant amounts of power to maintain operating temperature, and large installations had substantial air-conditioning requirements; replacing them with fetrons was expected to reduce cooling and maintenance costs. A typical fetron consisted of a cascode configured pair of JFETs, some simple RC networks to control the device characteristics, and a fuse. The device was mounted in a metal tube with a base that has the same pin-out as the vacuum tube that it replaced. Use Fetrons were used to upgrade oscilloscopes and similar test equipment. They were used ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vacuum Tube
A vacuum tube, electron tube, thermionic valve (British usage), or tube (North America) is a device that controls electric current flow in a high vacuum between electrodes to which an electric voltage, potential difference has been applied. It takes the form of an evacuated tubular envelope of glass or sometimes metal containing electrodes connected to external connection pins. The type known as a thermionic tube or thermionic valve utilizes thermionic emission of electrons from a hot cathode for fundamental Electronics, electronic functions such as signal amplifier, amplification and current Rectifier, rectification. Non-thermionic types such as vacuum phototubes achieve electron emission through the photoelectric effect, and are used for such purposes as the detection of light and measurement of its intensity. In both types the electrons are accelerated from the cathode to the anode by the electric field in the tube. The first, and simplest, vacuum tube, the diode or Flem ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
JFET
The junction field-effect transistor (JFET) is one of the simplest types of field-effect transistor. JFETs are three-terminal semiconductor devices that can be used as electronically controlled switches or resistors, or to build amplifiers. Unlike bipolar junction transistors, JFETs are exclusively voltage-controlled in that they do not need a biasing current. Electric charge flows through a semiconducting channel between ''source'' and ''drain'' terminals. By applying a reverse bias voltage to a ''gate'' terminal, the channel is '' pinched'', so that the electric current is impeded or switched off completely. A JFET is usually conducting when there is zero voltage between its gate and source terminals. If a potential difference of the proper polarity is applied between its gate and source terminals, the JFET will be more resistive to current flow, which means less current would flow in the channel between the source and drain terminals. JFETs are sometimes referred to a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mesa Boogie Mark Series
The Mesa/Boogie Mark Series is a series of guitar amplifier made by Mesa Boogie, Mesa Engineering (more commonly known as "Mesa/Boogie"). Originally just referred to as "Boogies", the product line took on the moniker "Mark Series" as newer revisions were put into production. The Mark Series amplifier was Mesa's flagship product until the introduction of the Mesa/Boogie Rectifier, Rectifier series, and the amplifiers are collectable. Mark I Randall Smith began Mesa/Boogie with a practical joke: he borrowed a Fender Princeton (a small 12-watt amplifier) from his friend, Barry Melton of Country Joe and the Fish, and "hotrodded" it by replacing the amplifier section with a powerful Fender Bassman amp and installing a 12-inch speaker instead of the original 10-inch. The resulting amplifier proved to be loud and successful, and Smith made more than 200 of these Princeton "Boogies" - a name allegedly provided by Carlos Santana, who is to have exclaimed "Man, that little thing really boog ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Solid-state Electronics
Solid-state electronics are semiconductor electronics: electronic equipment that use semiconductor devices such as transistors, diodes and integrated circuits (ICs). The term is also used as an adjective for devices in which semiconductor electronics that have no moving parts replace devices with moving parts, such as the solid-state relay, in which transistor switches are used in place of a moving-arm electromechanical relay, or the solid-state drive (SSD), a type of semiconductor memory used in computers to replace hard disk drives, which store data on a rotating disk. History The term ''solid-state'' became popular at the beginning of the semiconductor era in the 1960s to distinguish this new technology. A semiconductor device works by controlling an electric current consisting of electrons or holes moving within a solid crystalline piece of semiconducting material such as silicon, while the thermionic vacuum tubes it replaced worked by controlling a current of elect ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plug Compatible
Plug compatible refers to " hardware that is designed to perform exactly like another vendor's product." The term PCM was originally applied to manufacturers who made replacements for IBM peripherals. Later this term was used to refer to IBM-compatible computers. PCM and peripherals Before the rise of the PCM peripheral industry, computing systems were either configured with peripherals designed and built by the CPU vendor, or designed to use vendor-selected rebadged devices. The first example of plug-compatible IBM subsystems were tape drives and controls offered by Telex beginning 1965. Memorex in 1968 was first to enter the IBM plug-compatible disk followed shortly thereafter by a number of suppliers such as CDC, Itel, and Storage Technology Corporation. This was boosted by the world's largest user of computing equipment in both directions. Ultimately plug-compatible products were offered for most peripherals and system main memory. PCM and computer systems A plug-compatib ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cascode
The cascode is a two-stage amplifier that consists of a common emitter stage feeding into a common base stage when using bipolar junction transistors (BJTs) or alternatively a common source stage feeding a common gate stage when using field-effect transistors (FETs). Because there is no direct coupling from the output to input, the Miller effect is eliminated, contributing to a much higher bandwidth. Compared to a single amplifier stage, this combination may have one or more of the following characteristics: higher input–output isolation, higher input impedance, high output impedance, higher bandwidth (signal processing), bandwidth. History The use of a cascode (sometimes verbification, verbified to ''cascoding'') is a common technique for improving analog circuit performance, applicable to both vacuum tubes and transistors. The name "cascode" was coined in an article written by Frederick Vinton Hunt and Roger Wayne Hickman in 1939, in a discussion on the application of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
RC Circuit
A resistor–capacitor circuit (RC circuit), or RC filter or RC network, is an electric circuit composed of resistors and capacitors. It may be driven by a voltage source, voltage or current source and these will produce different responses. A first order RC circuit is composed of one resistor and one capacitor and is the simplest type of RC circuit. RC circuits can be used to filter a signal by blocking certain frequencies and passing others. The two most common RC filters are the high-pass filters and low-pass filters; band-pass filters and band-stop filters usually require RLC filters, though crude ones can be made with RC filters. Natural response The simplest RC circuit consists of a resistor with Electric resistance, resistance and a charged capacitor with capacitance connected to one another in a single loop, without an external voltage source. The capacitor will discharge its stored energy through the resistor. If is taken to be the voltage of the capacitor's top pl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Western Electric
Western Electric Co., Inc. was an American electrical engineering and manufacturing company that operated from 1869 to 1996. A subsidiary of the AT&T Corporation for most of its lifespan, Western Electric was the primary manufacturer, supplier, and purchasing agent for all telephone equipment for the Bell System from 1881 until 1984, when Breakup of the Bell System, the Bell System was dismantled. Because the Bell System had a near-total monopoly over telephone service in the United States for much of the 20th century, Western Electric's equipment was widespread across the country. The company was responsible for many technological innovations, as well as developments in industrial management. History 19th century In 1856, George Shawk, a craftsman and telegraph maker, purchased an electrical engineering business in Cleveland, Ohio. In January 1869, Shawk had partnered with Enos M. Barton in the former Western Union repair shop of Cleveland, to manufacture burglar alarms, fire ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
